Information communication terminal provided with security control function, communication system, and communication method performed by the terminal

ABSTRACT

A position information obtaining section  102  obtains position information indicating the current position of an information communication terminal  100 . A safety area storing section  103  stores in advance a safety area considered as being safe because the security risk such as information leak is low. A safety determination section  104  determines, based on the position information and the safety area, the security risk of wireless communication performed by the information communication terminal  100  at the current position. The communication control section  105  controls a wireless communication section  106  so as to transmit a radio signal at a larger radio wave intensity when the safety determination section  104  has determined that the risk is low, and to transmit a radio signal at a smaller radio wave intensity when the safety determination section  104  has determined that the risk is high.

TECHNICAL FIELD

The present invention relates to information communication terminalsprovided with security control functions, and more specifically, toinformation communication terminals configured to control a radio waveintensity by using position information in order to improve security ofcommunication performed between the information communication terminals,a communication system including a plurality of the informationcommunication terminals, and a communication method performed by theinformation communication terminals.

BACKGROUND ART

In recent years, more people own a plurality of informationcommunication terminals that can execute applications, such as desktoppersonal computer (hereinafter, referred to as PC), notebook PC, tabletPC, PDA (personal digital assistant), mobile phone, smartphone, and thelike, and use a plurality of information communication terminalsdifferently in accordance with situations. Moreover, progress ofhardware installed in these information communication terminals has beenremarkable. For example, an information communication terminal includesa CPU (central processing unit) having a gigahertz-class clockfrequency, and has a plurality of communication means such as publiccircuit, wireless LAN, (Local Area Network), Bluetooth®, and the like.Accordingly, Web sites made for PCs have been increasingly browsed atvarious locations, by means of not only PCs but also smartphones. Thus,there is a demand for a seamless terminal transfer in which, when aplurality of information communication terminals to be used areswitched, an application, such as a browser, being used in aninformation communication terminal which is a transfer source can becontinuously used in an information communication terminal which is atransfer destination.

On the other hand, there are many cases where data handled bysmartphones and the like is personal information. For example, manypeople visit shopping sites by using browsers and input personalinformation such as address, credit card number, and the like. Inaddition, an access history by use of a browser and bookmark informationare privacy-related data, and thus, people may not want such informationto be viewed by others. That is, when such information is relayedbetween information communication terminals, it is necessary to payutmost attention so as to prevent such information from leaking andbeing misused.

Further, smartphones are easy to carry and used at various locations.Therefore, if a GPS (Global Positioning System) is installed in asmartphone, it is possible to correctly identify the position at whichthe smartphone is used. By using this position information, it ispossible to improve not only convenience but also security at the timewhen privacy-related data is communicated.

An example of a conventional technology that improves security duringcommunication by using position information of an informationcommunication terminal is the technology disclosed in PatentLiterature 1. According to the technology disclosed in Patent Literature1, information of the location and time at which electronic commerce isto be performed is registered in a server in advance. Then, whenperforming electronic commerce by accessing a server, an informationcommunication terminal obtains the current location and time andtransmits them as authentication information to the server. Only whenthe information registered in advance coincides with the transmittedinformation, the server allows electronic commerce. In this manner, thetechnology disclosed in Patent Literature 1 enhances the security duringcommunication.

CITATION LIST Patent Literature

-   [PTL 1] Japanese Laid-Open Patent Publication No. 2006-244381

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

According to the above conventional technology, by registering, in aserver, position information of an information communication terminalused when performing communication with the server, the accuracy of anauthentication process regarding the information communication terminalis improved, and the security of communication between the informationcommunication terminal and the server can be enhanced. However, althoughthe information communication terminal is a portable device that can becarried around, the server is, in a common understanding, not anapparatus that can be carried around and is fixed to a certain place.That is, the above conventional technology is not a technology made inconsideration of solving security problems characteristic tocommunications between information communication terminals that can bothbe carried around.

For example, in a relatively large house, a radio wave containinginformation does not leak to the outside of the house. However, in asmall house, a radio wave containing information leaks to the outside ofthe house, and the possibility of the information being stolen byanother person is increased. Further, in a public place such as in atrain, since there are many people having multiple terminals nearby, aninformation leak risk of the information being stolen is furtherincreased. That is, although the information leak risk at the time whenperforming communication between information communication terminalschanges depending on the location, a communication method cannot,conventionally, be changed in accordance with the change of theinformation leak risk, and the security cannot be improved.

Therefore, an object of the present invention is to provide a securitycontrol device that can determine, when communication is performedbetween information communication terminals, a security risk based onposition information of a terminal, and change the communication methodin accordance with the determination, thereby ensuring security andimproving communication efficiency and convenience between theinformation communication terminals; a communication system; and acommunication method performed by the terminals.

Solution to the Problems

The present invention is directed to an information communicationterminal configured to perform wireless communication using shortdistance communication. In order to attain the above object, theinformation communication terminal of the present invention includes: aposition information obtaining section configured to obtain positioninformation of the information communication terminal; a safety areastoring section configured to store a safety area registered as beingsafe when the information communication terminal performs communicationwith another terminal; a safety determination section configured todetermine, based on the position information of the informationcommunication terminal and the safety area, a security risk at the timewhen the information communication terminal performs communication withthe another terminal; and a communication section configured to perform,when the safety determination section has determined that the securityrisk during communication is high, data communication with the anotherterminal at a predetermined smaller radio wave intensity, and perform,when the safety determination section has determined that the securityrisk during communication is low, data communication with the anotherterminal at a predetermined larger radio wave intensity.

Typically, the safety area is inputted by the user through an inputsection through which the user inputs an instruction. Alternatively, thesafety area may be determined by the position information obtainingsection based on a history of a plurality of pieces of positioninformation that have been obtained.

Preferably, when the position information obtaining section has failedto obtain the position information of the information communicationterminal, the safety determination section determines that the securityrisk during communication is high. Further, the safety determinationsection determines the security risk during communication, depending onwhether a current position of the information communication terminalobtained from the position information is present within the safetyarea. At this time, the safety determination section may determine thesecurity risk during communication, further based on informationobtainment time obtained from the position information.

It should be noted that, preferably, when the communication section canobtain position information of the another terminal, the safetydetermination section determines, further based on the positioninformation of the another terminal, the security risk at the time whenthe information communication terminal performs communication with theanother terminal. Further, in this case, at a timing when the distancebetween the information communication terminal and the another terminalhas become a distance that allows communication at a radio waveintensity determined based on the determination by the safetydetermination section, the communication section can start datacommunication.

Advantageous Effects of the Invention

According to the present invention, when the risk determined based onthe position information of the terminal is high, the security can beincreased even by decreasing the communication ability, and when therisk determined based on the position information of the terminal islow, the communication ability can also be increased with the securitybeing ensured. Accordingly, the communication ability and the securitycan be optimally controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a configuration of a communication systemincluding information communication terminals provided by the presentinvention.

FIG. 2 shows an example of a display screen 11 of a tablet PC 10 and adisplay screen 21 of a mobile phone 20.

FIG. 3 shows an example of a configuration of an informationcommunication terminal 100 according to a first embodiment of thepresent invention.

FIG. 4 shows an example of position information obtained by a positioninformation obtaining section 102.

FIG. 5 shows an example of a safety area stored in a safety area storingsection 103.

FIG. 6 is a flow chart showing process steps of a radio wave intensitycontrol performed by the information communication terminal 100according to the first embodiment of the present invention.

FIG. 7 shows an example of a configuration of an informationcommunication terminal 200 according to a second embodiment of thepresent invention.

FIG. 8 shows an example of position information of a transferdestination terminal, stored in a transfer destination terminal positioninformation storing section 209.

FIG. 9 is a flow chart showing process steps of a radio wave intensitycontrol performed by the information communication terminal 200according to the second embodiment of the present invention.

FIG. 10 illustrates a specific example to which the present invention isapplied.

DESCRIPTION OF EMBODIMENTS

Hereinafter an embodiment of the present invention will be describedwith reference to the drawings.

In the present invention, a situation is assumed where, when a userswitches an information communication terminal being used by the user(hereinafter, referred to as transfer source terminal) to anotherterminal (hereinafter, referred to as transfer destination terminal),the user is to continuously use the application having been used in thetransfer source terminal, also in the transfer destination terminal. Insuch a situation, information such as operation contents performed ontothe application in the transfer source terminal is transmitted to thetransfer destination terminal. As a result, the operation contents andthe like of the application that the user was using in the transfersource terminal before the switch is reproduced and displayed on thescreen of the transfer destination terminal.

FIG. 1 shows an example of a configuration of a communication systemincluding an information communication terminal provided by the presentinvention. In the example of FIG. 1, one user owns a plurality ofinformation communication terminals, that is, a tablet PC 10, a mobilephone 20, and a notebook PC 30, which are connectable to a network 40.The user uses these information communication terminals differently inaccordance with situations. For example, the user uses the notebook PC30 in his or her house, and uses the tablet PC 10 or the mobile phone 20when the user is out. In such a communication system, it is conceivablethat, for example, the user was viewing internet news on a Web site onthe notebook PC 30 in the house, but since the time for going out hascome, the user views a continuation of the news on the mobile phone 20.Meanwhile, it is also conceivable that, for example, although the userwas viewing internet news on a Web site on the mobile phone 20 whilestanding in a train while the user was out, a seat became available, andthe user has taken the seat and thus views a continuation of the news onthe tablet PC 10 having a big screen, by switching the mobile phone 20to the tablet PC 10.

An example of display screens of the tablet PC 10 and the mobile phone20 when viewing internet news is shown in FIG. 2. FIG. 2 shows anexample of a display screen 11 of the tablet PC 10 and a display screen21 of the mobile phone 20.

The tablet PC 10 and the mobile phone 20 of the present embodiment areeach provided with a communication function for connecting to a network,and a part of a Web site obtained by the communication function is beingdisplayed on each of the display screens 11 and 21. It should be notedthat switching from the mobile phone 20 to the tablet PC 10 may beperformed in accordance with an instruction through a physical button ora software key provided in the mobile phone 20 being a transfer sourceterminal, or may be automatically performed by a predetermined statuschange being detected.

With respect to the usage described above, the switching direction maybe in the reverse, of course. That is, each of the informationcommunication terminals such as the tablet PC 10, the mobile phone 20,and the notebook PC 30 can be either of a transfer source terminal or atransfer destination terminal.

In each embodiment of the present invention, a configuration of aninformation communication terminal which can be at least a transfersource terminal, and processes performed by the informationcommunication terminal will be described in detail.

First Embodiment

FIG. 3 shows an example of a configuration of an informationcommunication terminal 100 according to a first embodiment of thepresent invention. The information communication terminal 100 accordingto the first embodiment shown in FIG. 3 includes an input section 101, aposition information obtaining section 102, a safety area storingsection 103, a safety determination section 104, a communication controlsection 105, a wireless communication section 106, a data storingsection 107, and an application section 108.

The input section 101 is an interface, such as a keypad and a touchpanel, through which a user inputs an instruction (request to startcommunication, information registration, and the like) to theinformation communication terminal 100. The user instruction inputted tothe input section 101 is outputted to the position information obtainingsection 102 and the application section 108.

The position information obtaining section 102 obtains positioninformation indicating the current position of the informationcommunication terminal 100. Typically, the position informationobtaining section 102 obtains the position information by receiving GPSinformation. Alternatively, the position information obtaining section102 may estimate a current position based on a MAC (Media AccessControl) address and a radio wave intensity received from a WiFi(Wireless Fidelity) access point, and may obtain the estimated currentposition as the position information. Still alternatively, the positioninformation obtaining section 102 may estimate a current position from aradio wave received from a mobile phone base station, and may obtain theestimated current position as the position information. Stillalternatively, the position information obtaining section 102 mayestimate a current position from an IP (Internet Protocol) address orthe like designated on the network, and may obtain the estimated currentposition as the position information.

FIG. 4 shows an example of position information obtained by the positioninformation obtaining section 102. With reference to the example in FIG.4, the obtainment time at which GPS information was received (Feb. 10,14:00, 2011), and the latitude (north latitude: 34 degrees, 44 minutes,and 36.02 seconds) and the longitude (east longitude: 135 degrees, 26minutes, and 44.35 seconds) of the current position of the informationcommunication terminal 100 are used as the position information.

The safety area storing section 103 is a memory for storing in advance asafety area which is registered as being safe, because in which safetyarea, when the information communication terminal 100 being used is tobe switched, even if necessary information is transmitted via wirelesscommunication from the transfer source terminal to the transferdestination terminal, a security risk such as information leak is low.As the safety area storing section 103, a non-volatile flash memory ispreferable. However, as long as the safety area is set every time theinformation communication terminal 100 is activated, a volatile memorymay be used. The safety area may be set manually by the user, or may beautomatically set by the information communication terminal 100. In thelatter case, it is conceivable that, for example, the informationcommunication terminal 100 extracts, based on a movement history, alocation where the information communication terminal 100 is relativelyoften present, and sets the extracted location or a neighborhood thereofas the safety area. Alternatively, the safety area storing section 103may set in advance a rule that the safety area should satisfy, such as“position at which GPS information can be detected”.

FIG. 5 shows an example of a safety area stored in the safety areastoring section 103. In the example of FIG. 5( a), an area having aradius of 30 meters about the position of 34 degrees, 39 minutes, and55.16 seconds in the north latitude, and 135 degrees, 30 minutes, and18.98 seconds in the east longitude is used as the safety area. In theexample of FIG. 5( b), a rectangle area having diagonal vertices at theposition of a north latitude N1 and an east longitude E1, and theposition of a north latitude N2 and an east longitude E2 is used as thesafety area. Although the safety areas shown in the examples in FIG. 5have simple shapes such as a circle or a rectangle, an area having acomplicated shape other than these shapes may be used as the safetyarea.

The safety determination section 104 receives the position informationobtained by the position information obtaining section 102 and thesafety area stored in the safety area storing section 103, anddetermines a security risk in wireless communication performed by theinformation communication terminal 100. Specifically, when theinformation communication terminal 100 (transfer source terminal) ispresent within the safety area, the safety determination section 104determines that even if the information communication terminal 100performs, at the current position, wireless communication with anotherneighboring information communication terminal (transfer destinationterminal), it is safe because the security risk is low. On the otherhand, when the information communication terminal 100 is not presentwithin the safety area, the safety determination section 104 determinesthat if the information communication terminal 100 performs, at thecurrent position, wireless communication with another neighboringinformation communication terminal, it is dangerous because the securityrisk is high.

Based on the result determined by the safety determination section 104,the communication control section 105 controls the radio wave intensityof a radio signal to be transmitted by the wireless communicationsection 106. Specifically, when the determination result by the safetydetermination section 104 is “safe”, the communication control section105 instructs the wireless communication section 106 to increase theradio wave intensity of the radio signal, and when the determinationresult by the safety determination section 104 is “dangerous”, thecommunication control section 105 instructs the wireless communicationsection 106 to decrease the radio wave intensity of the radio signal.

The wireless communication section 106 is an interface for performingwireless communication with another information communication terminal.The wireless communication section 106 may be any interface that cantransmit and receive a radio signal to and from another informationcommunication terminal present at a short distance therefrom, and forexample, WiFi, Bluetooth, or the like can be used. The wirelesscommunication section 106 forms, along with the communication controlsection 105 described above, a communication section of the informationcommunication terminal 100.

The data storing section 107 is a memory for storing data to betransmitted by the information communication terminal 100 when theinformation communication terminal 100 performs wireless communicationwith another information communication terminal present at a shortdistance therefrom. In the present invention, it is assumed that datastored in the data storing section 107 includes personal information andthe like which require security. A flash memory, a DRAM (Dynamic RandomAccess Memory), or the like is used as the data storing section 107.

The application section 108 is an application that uses data stored inthe data storing section 107, and is a Web browser, for example. Ingeneral, the application section 108 is stored in a ROM (Read OnlyMemory) included in the information communication terminal 100, is readfrom the ROM when necessary, and executed by use of the CPU and a RAM(Random Access Memory). It should be noted that in the configuration ofthe information communication terminal 100 shown in FIG. 3, the CPU, theRAM, and the ROM are omitted.

Next, steps of wireless communication performed by the informationcommunication terminal 100 according to the first embodiment having theabove-described configuration with another information communicationterminal present at a short distance will be described further withreference to FIG. 6.

FIG. 6 is a flow chart showing process steps of a radio wave intensitycontrol performed by the information communication terminal 100according to the first embodiment of the present invention. It should benoted that a safety area is stored in advance in the safety area storingsection 103, as described above.

The process shown in FIG. 6 is started by the input section 101receiving an instruction to start communication from a user. The inputsection 101 having received an instruction to start communication fromthe user notifies the position information obtaining section 102 of aposition information obtaining request. Upon receiving the notification,the position information obtaining section 102 obtains positioninformation indicating the current position of the informationcommunication terminal 100 (step S50). The obtained position informationis outputted to the safety determination section 104.

The safety determination section 104 obtains the position informationfrom the position information obtaining section 102 and the safety areafrom the safety area storing section 103, and determines whether thesecurity risk is low or high, based on whether the informationcommunication terminal 100 is present within the safety area (step S51).When determining that the information communication terminal 100 ispresent within the safety area (step S51, Yes), the safety determinationsection 104 notifies the communication control section 105 of adetermination that even if the information communication terminal 100performs, at the current position, wireless communication with anotherinformation communication terminal, it is safe because the security riskis low. On the other hand, when determining that the informationcommunication terminal 100 is not present within the safety area (stepS51, No), the safety determination section 104 notifies thecommunication control section 105 of a determination that if theinformation communication terminal 100 performs, at the currentposition, wireless communication with another information communicationterminal, it is dangerous because the security risk is high.

Whether the position of the information communication terminal 100 iswithin the safety area is determined by the safety determination section104 in the following manner, for example.

When the safety area is stored as a circular area as in the case of FIG.5( a), a distance D between the center of the safety area and thecurrent position of the information communication terminal 100 isdetermined, and the distance D is compared with the radius r of thesafety area. If the distance D≦the radius r is satisfied, it isdetermined that the information communication terminal 100 is presentwithin the safety area. It should be noted that although the earth is asphere, a meridian between two points that are very close to each othercan be regarded as a straight line, and thus, the distance D can bedetermined by approximate calculation using a simple trigonometricfunction.

Further, when the safety area is stored as a rectangular area as in thecase of FIG. 5( b), a latitude N of the information communicationterminal 100 is compared with each of the values of the north latitudesN1 and the N2, and a longitude E of the information communicationterminal 100 is compared with each of the values of the east longitudesE1 and E2. If the north latitude N1≦the latitude N≦the north latitudeN2, and the east longitude E1≦the longitude E≦the east longitude E2 aresatisfied, it is determined that the information communication terminal100 is present within the safety area.

When receiving, from the safety determination section 104, anotification that it is safe because the security risk is low, thecommunication control section 105 issues an instruction, to the wirelesscommunication section 106, to set the radio wave intensity used whentransmitting a radio signal to a larger value that has been set inadvance (step S52). On the other hand, when receiving, from the safetydetermination section 104, a notification that it is dangerous becausethe security risk is high, the communication control section 105 issuesan instruction, to the wireless communication section 106, to set theradio wave intensity used when transmitting a radio signal to a smallervalue that has been set in advance (step S53). Then, the communicationcontrol section 105 obtains, from the data storing section 107, data tobe transmitted through wireless communication, and transmits, throughthe wireless communication section 106, the obtained data to anotherinformation communication terminal, in a radio signal having the radiowave intensity set in step S52 or step S53 (step S54).

As described above, in the information communication terminal 100according to the first embodiment of the present invention, when the ownterminal (transfer source terminal) is present in the safety area set inadvance, wireless communication is performed with another informationcommunication terminal (transfer destination terminal), by using a radiosignal having a larger radio wave intensity, and when the own terminalis not present in the safety area set in advance, wireless communicationis performed with another information communication terminal, by using aradio signal having a smaller radio wave intensity. Accordingly, it ispossible to perform control, such that, when the security riskdetermined based on the position information of the informationcommunication terminal is high, the safety is prioritized to beincreased even by decreasing the communication ability, and when thesecurity risk determined based on the position information of theinformation communication terminal is low, communication is allowed tobe performed with another terminal, with increased communication abilitywhile a certain level of safety being maintained. Accordingly, it ispossible to improve the communication efficiency and convenience betweeninformation communication terminals while maintaining the security.

Second Embodiment

FIG. 7 shows an example of a configuration of an informationcommunication terminal 200 according to a second embodiment of thepresent invention. The information communication terminal 200 accordingto the second embodiment shown in FIG. 7 includes the input section 101,the position information obtaining section 102, the safety area storingsection 103, a safety determination section 204, a communication controlsection 205, a wireless communication section 206, the data storingsection 107, the application section 108, and a transfer destinationterminal position information storing section 209. As shown in FIG. 7,the information communication terminal 200 according to the secondembodiment is different from the information communication terminal 100(FIG. 3) according to the first embodiment, in terms of theconfigurations of the safety determination section 204, thecommunication control section 205, the wireless communication section206, and the transfer destination terminal position information storingsection 209.

The transfer destination terminal position information storing section209 is a memory for storing position information indicating the currentposition of a transfer destination terminal 220, which serves as anotherinformation communication terminal to which the data stored in the datastoring section 107 is to be transmitted. FIG. 8 shows an example ofposition information of a transfer destination terminal stored in thetransfer destination terminal position information storing section 209.In the example of FIG. 8, the reception time (Feb. 14, 14:00, 2011), andthe latitude (north latitude: 34 degrees, 44 minutes, and 36.00 seconds)and the longitude (east longitude: 135 degrees, 26 minutes, and 44.30seconds) of the current position of the transfer destination terminalare stored as the position information. It should be noted that theposition information to be stored may be any information that canspecify the position of the transfer destination terminal 220, and maybe indicated by relative coordinates or the like with the informationcommunication terminal 200, instead of absolute coordinates.

The safety determination section 204, the communication control section205, and the wireless communication section 206 of the second embodimentdiffer from the safety determination section 104, the communicationcontrol section 105, and the wireless communication section 106 of thefirst embodiment in that a process for storing position information ofthe transfer destination terminal, and a process of safety determinationusing the position information of the transfer destination terminal arefurther performed. It should be noted that the communication controlsection 205 and the wireless communication section 206 form acommunication section of the information communication terminal 200.

Hereinafter, the information communication terminal 200 according to thesecond embodiment will be described, focusing on the above differentfeatures thereof. The same components as those of the informationcommunication terminal 100 according to the first embodiment are denotedby the same reference characters, and description thereof will beomitted.

FIG. 9 is a flow chart showing process steps of a radio wave intensitycontrol performed by the information communication terminal 200according to the second embodiment of the present invention. It shouldbe noted that the safety area is stored in advance in the safety areastoring section 103 as described above.

The process shown in FIG. 9 is started by the input section 101receiving an instruction to start communication from a user. The inputsection 101 having received an instruction to start communication fromthe user notifies the position information obtaining section 102 of aposition information obtaining request. Upon receiving the notification,the position information obtaining section 102 obtains positioninformation indicating the current position of the informationcommunication terminal 100 (step S50). The obtained position informationis outputted to the safety determination section 104. Concurrently, theinput section 101 notifies the communication control section 205 of aposition information obtaining request regarding the transferdestination terminal. Upon receiving the notification, the communicationcontrol section 205 searches for the transfer destination terminal 220through the wireless communication section 206, and requests the foundtransfer destination terminal 220 to notify the communication controlsection 205 of position information (step S61).

When having able to receive a response to this request from the transferdestination terminal 220 through the wireless communication section 206and to obtain the position information of the transfer destinationterminal (step S62, Yes), the communication control section 205 storesthe position information of the transfer destination terminal in thetransfer destination terminal position information storing section 209(step S63). On the other hand, when not having able to obtain theposition information of the transfer destination terminal even afterhaving waited for a certain period (step S62, No), the communicationcontrol section 205 determines that the transfer destination terminal isin a state where it cannot perform communication, and ends the process.

Upon the position information of the transfer destination terminal beingstored, the safety determination section 204 obtains the positioninformation from the position information obtaining section 102, thesafety area from the safety area storing section 103, the positioninformation of the transfer destination terminal from the transferdestination terminal position information storing section 209, anddetermines whether the security risk is high or low based on thesepieces of information and the area (step S51). For example, if both ofthe current position of the information communication terminal 200 andthe current position of the transfer destination terminal 220 arepresent within the safety area, the safety determination section 204notifies the communication control section 205 of a determination thateven if wireless communication is performed between the terminals, it issafe because the security risk is low (step S51, Yes). On the otherhand, if neither of the current position of the informationcommunication terminal 200 nor the current position of the transferdestination terminal 220 are present within the safety area, the safetydetermination section 204 notifies the communication control section 205of a determination that if wireless communication is performed betweenthe terminals, it is dangerous because the security risk is high (stepS51, No). It should be noted that, in a case where only one of theterminals is present within the safety area, a process of determiningthe security risk as being medium and setting the radio wave intensityto a medium value may be performed.

When receiving, from the safety determination section 204, anotification that it is safe because the security risk is low, thecommunication control section 205 issues an instruction, to the wirelesscommunication section 206, to set the radio wave intensity used whentransmitting a radio signal to a larger value that has been set inadvance (step S52). On the other hand, when receiving, from the safetydetermination section 204, a notification that it is dangerous becausethe security risk is high, the communication control section 205 issuesan instruction, to the wireless communication section 206, to set theradio wave intensity used when transmitting a radio signal to a smallervalue that has been set in advance (step S53). Then, the communicationcontrol section 205 obtains, from the data storing section 107, data tobe transmitted through wireless communication, and transmits, throughthe wireless communication section 206, the obtained data to thetransfer destination terminal 220, in a radio signal having the radiowave intensity set in step S52 or step S53 (step S54).

As described above, in the information communication terminal 200according to the second embodiment of the present invention, the radiowave intensity of a radio signal is set, by judging, in addition to thecurrent position of the own terminal (transfer source terminal), thecurrent position of the another terminal (transfer destinationterminal). Accordingly, it is possible to further improve the securityin addition to the effects provided by the first embodiment.

In the above embodiments, the cases where the safety area is stored inadvance in the safety area storing section 103 have been described.However, the safety area may not be stored in advance in each of theinformation communication terminals 100 and 200, and may be storedsequentially. For example, each of the information communicationterminals 100 and 200 may always receive GPS information, may determine,based on the history of a plurality of pieces of position informationthat have been received, a specific area such as an area where thecorresponding information communication terminal 100 or 200 frequentlypasses, and may register the determined specific area as the safety areain the safety area storing section 103. Through such a process, it ispossible to eliminate the necessity for the user to explicitly registerthe safety area.

Further, in the above embodiments, description has been given of thecases where the current position of each of the informationcommunication terminals 100 and 200 is detected by use of GPSinformation, or a MAC address and a radio wave intensity received from aWiFi access point, and the detected current position is compared withthe safety area. However, there may be cases where the current positionsof the information communication terminals 100 and 200 cannot bedetected. Therefore, in such a case where there is no information to becompared with the safety area, it may be determined that the securityrisk is high and it is dangerous.

Further, in the above embodiments, description has been given of thecases where security risk determination is performed based on thecurrent position and the safety area of each of the informationcommunication terminals 100 and 200. However, security riskdetermination may be performed also based on the current time inaddition to the current position. For example, even in the case of aplace that has a big crowd during the daytime and that seems to have ahigh security risk, if the place has only a small number of people inthe early morning and has a good commanding view, there may besituations where it can be determined that the security risk isrelatively low. Therefore, in such a case, even if the informationcommunication terminal 100 or 200 is not present within the safety area,if the current time is an early time in the morning, it is possible todetermine that the security risk is low.

Further, in the above embodiments, description has been given of thecases where the radio wave intensity is controlled in two patterns, thatis, large or small. However, a plurality of radio wave intensities maybe used in accordance with the level of the security risk. In this case,by storing security risk levels associated with the respective pluralityof safety areas, the safety area storing section 103 can manage suchcontrol.

Further, in the above embodiments, description has been given on thecases where communication between information communication terminals isstarted upon an operation performed by the user. However, in a casewhere one or both of the two information communication terminals forwhich switching is performed is(are) moving, communication may beautomatically started if the distance between the two informationcommunication terminals becomes smaller than a predetermined value. Thispredetermined value is, for example, a distance which allows data toreach the transfer destination terminal at a radio wave intensityappropriate for avoiding the risk, which has been determined by thecommunication control section 105 or 205.

<Specific Application Example of the Present Invention>

As described at the beginning, in a case where one user owns a pluralityof information communication terminals, there may be a situation wherethe user wants the Web site that the user having been browsing on thetablet PC 10 while the user has been out, to be seamlessly switched tothe notebook PC 30 in the user's house when the user returns home, suchthat the user can continuously browse the Web site. In such a situation,activation of the browser application, obtainment of HTML documents fordisplaying the Web site being browsed, and transfer data regarding theaccess history and the like need to be transmitted to the transferdestination terminal. Since transmission of such transfer data takessome time, it is preferable, for realization of seamless transition,that communication of transfer data is started in advance (hereinafter,referred to as “pre-fetch communication”). The technology provided bythe present invention is applicable to this pre-fetch communication.

For example, an area having a radius 50 m around the user's house isdefined as the safety area, and upon the tablet PC 10 being the transfersource terminal entering the safety area, the tablet PC 10 automaticallystarts pre-fetch communication with the notebook PC 30 in the house(FIG. 10). Alternatively, the safety area is provided in ranks, andwhile the tablet PC 10 is far from the house (radius 100 m), pre-fetchcommunication may be performed at a smaller radio wave intensity, andwhen the tablet PC 10 comes near the house (radius 20 m), pre-fetchcommunication may be performed at a larger radio wave intensity. By thisprocess, all or most of the communication for the transfer is completedby the time the user reaches the house, and the user can immediatelycontinue browsing the Web site. With respect to the distance at whichthe pre-fetch communication is started, a predetermined value may bedetermined that is sufficient for completing the pre-fetch process,based on the amount of data to be transferred, the communication speed,the movement speed of the terminal, and the like.

A part or the whole of the functional blocks forming the informationcommunication terminal in each embodiment of the present invention isrealized by using hardware resources such as a central processing unit(CPU), a storage device (memory (ROM, RAM, etc.), hard disk, etc.), andthe input/output device, and typically implemented as an IC being anintegrated circuit (also referred to as LSI, system LSI, super LSI,ultra LSI, etc.). These functional blocks may be implemented inindividual chips, or a part or the whole of them may be implemented inone chip.

Further, the method for circuit integration is not limited to the IC,and may be realized by a dedicated circuit or a general-purposeprocessor. An FPGA (Field Programmable Gate Array) that can beprogrammed after manufacture of the IC or a reconfigurable processorthat allows connections and settings of the circuit cells in the IC tobe reconfigured may be used.

Still further, in a case where another circuit integration technology(such as biotechnology) replacing the IC becomes available as a resultof improvement of a semiconductor technology or emergence of anothertechnology derived therefrom, the functional blocks may be, of course,integrated using the technology

The communication method performed by the information communicationterminal in each embodiment of the present invention described above maybe realized by the CPU interpreting and executing predetermined programdata capable of executing the processes of the communication methodstored in the storage device. In this case, the program data may beloaded onto the storage device via a storage medium such as a CD-ROM, aflexible disk, or the like, or may be directly executed on the storagemedium. Here, the storage medium includes: a semiconductor memory suchas a ROM, a RAM, and a flash memory; a magnetic disk memory such as aflexible disk, and a hard disk; an optical disk memory such as a CD-ROM,a DVD, and a BD; a memory card; and the like. Further, the storagemedium is a notion including a communication medium such as a telephoneline, a carrier path, and the like.

INDUSTRIAL APPLICABILITY

The present invention can be used in an information communicationterminal capable of executing applications, a system including theterminal, and the like. In particular, the present invention is usefulin a case, for example, where it is desired to improve communicationefficiency and convenience between information communication terminals,while maintaining the security.

DESCRIPTION OF THE REFERENCE CHARACTERS

-   -   10 tablet PC    -   11, 21 display screen    -   20 mobile phone    -   30 notebook PC    -   40 network    -   100, 200 information communication terminal    -   101 input section    -   102 position information obtaining section    -   103 safety area storing section    -   104, 204 safety determination section    -   105, 205 communication control section    -   106, 206 wireless communication section    -   107 data storing section    -   108 application    -   209 transfer destination terminal position information storing        section    -   220 transfer destination terminal

1. An information communication terminal configured to perform wirelesscommunication using short distance communication, comprising: a positioninformation obtaining section configured to obtain position informationof the information communication terminal; a safety area storing sectionconfigured to store a safety area registered as being safe when theinformation communication terminal performs communication with anotherterminal; a safety determination section configured to determine, basedon the position information of the information communication terminaland the safety area, a security risk at the time when the informationcommunication terminal performs communication with the another terminal;and a communication section configured to perform, when the safetydetermination section has determined that the security risk duringcommunication is high, data communication with the another terminal at apredetermined smaller radio wave intensity, and perform, when the safetydetermination section has determined that the security risk duringcommunication is low, data communication with the another terminal at apredetermined larger radio wave intensity.
 2. The informationcommunication terminal according to claim 1, further comprising: aninput section through which a user inputs an instruction, wherein thesafety area is inputted by the user through the input section.
 3. Theinformation communication terminal according to claim 1, wherein theposition information obtaining section determines the safety area, basedon a history of a plurality of pieces of position information that havebeen obtained.
 4. The information communication terminal according toclaim 1, wherein when the position information obtaining section hasfailed to obtain the position information of the informationcommunication terminal, the safety determination section determines thatthe security risk during communication is high.
 5. The informationcommunication terminal according to claim 1, wherein the safetydetermination section determines the security risk during communication,depending on whether a current position of the information communicationterminal obtained from the position information is present within thesafety area.
 6. The information communication terminal according toclaim 5, wherein the safety determination section determines thesecurity risk during communication, further based on informationobtainment time obtained from the position information.
 7. Theinformation communication terminal according to claim 1, wherein thecommunication section obtains position information of the anotherterminal, and the safety determination section determines, further basedon the position information of the another terminal, the security riskat the time when the information communication terminal performscommunication with the another terminal.
 8. The informationcommunication terminal according to claim 7, wherein at a timing whenthe distance between the information communication terminal and theanother terminal has become a distance that allows communication at aradio wave intensity determined based on the determination by the safetydetermination section, the communication section starts datacommunication.
 9. A communication system including a first and a secondinformation communication terminals that each perform wirelesscommunication using short distance communication, the first informationcommunication terminal comprising: a position information obtainingsection configured to obtain position information of the firstinformation communication terminal; a safety area storing sectionconfigured to store a safety area registered as being safe when thefirst information communication terminal performs communication with thesecond information communication terminal; a safety determinationsection configured to determine, based on the position information andthe safety area, a security risk at the time when the first informationcommunication terminal performs communication with the secondinformation communication terminal; and a communication sectionconfigured to perform, when the safety determination section hasdetermined that the security risk during communication is high, datacommunication with the second information communication terminal at apredetermined smaller radio wave intensity, and performs, when thesafety determination section has determined that the security riskduring communication is low, data communication with the secondinformation communication terminal at a predetermined larger radio waveintensity.
 10. A communication method performed by an informationcommunication terminal configured to perform wireless communicationusing short distance communication, the method comprising the steps of:obtaining position information of the information communicationterminal; determining, based on the position information and a safetyarea registered as being safe when the information communicationterminal performs communication with another terminal, the safety areabeing stored in advance, a security risk at the time when theinformation communication terminal performs communication with theanother terminal; and performing, when it is determined that thesecurity risk during communication is high in the determination step,data communication with the another terminal at a predetermined smallerradio wave intensity, and performing, when it is determined that thesecurity risk during communication is low in the determination step,data communication with the another terminal at a predetermined largerradio wave intensity.